slack.target-push-api
Background
By default, messages will be submitted to the push endpoint running
on the default local admin port (i.e. https://localhost:8443/push-api/
).
If the configured admin port differs, or if you wish to configure slack to use the push endpoint on a different machine, it can be configured here.
Note that if targeting a different machine, the server secrets must match to allow service users to communicate between the machines in question.